Endocrine gland located close to and behind the thyroid gland. Humans typically have four parathyroid glands. Each gland secretes parathyroid hormone, which regulates blood calcium and phosphate levels. When serum calcium concentrations drop, increased hormone secretion releases calcium from bone into the bloodstream (see calcium deficiency). An increase in parathyroid hormone secretion also increases excretion of phosphate in the urine, thereby lowering serum phosphate concentrations. In addition, the hormone regulates magnesium metabolism by increasing its excretion. When thyroid removal is required, the parathyroid glands must be separated out and left in place to avoid hypoparathyroidism (parathyroid hormone deficiency). See also endocrine system.
This entry comes from Encyclopædia Britannica Concise.
For the full entry on parathyroid gland, visit Britannica.com.
Seen & Heard
What made you look up parathyroid gland? Please tell us what you were reading, watching or discussing that led you here.